bio notes 3/5/25

Passive Transport

• Hypertonic Solution

  • Characterized by a high concentration of solute and low concentration of water.

  • Effect on Cells: Water exits the cell, resulting in cell shrinkage.

    • Red Blood Cells: Cells shrivel due to water loss (termed crenation).

    • Plasma Membrane: The cell membrane shrinks away from the cell wall, a condition referred to as plasmolysis.

Key Terms

• Crenate: Describes the shrunken state of cells in a hypertonic solution.

• Turgor: The pressure of the cell contents against the cell wall in a plant cell, maintaining its shape and firmness.

• Osmoregulate: Mechanisms employed by organisms to maintain water balance.

Active Transport

• Definition: Movement of molecules across a membrane using energy (ATP).

• Types of Active Transport:

  • Uses specific proteins to move substances:

    • Uniport: Transports one type of substance in one direction.

    • Symport: Transports two different substances in one direction.

    • Antiport: Transports two different substances in opposite directions.

  • Vesicle Transport: Movement of materials via vesicles:

    • Endocytosis: The process of bringing materials into the cell by forming vesicles.

      • Types of Endocytosis:

        • Phagocytosis: Engulfment of solids (e.g., white blood cells (lymphocytes) engulfing bacteria).

        • Pinocytosis: Engulfment of liquids.

Endosymbiotic Theory

• Refers to how chloroplasts and mitochondria may have entered early eukaryotic cells as independent prokaryotic organisms, contributing to the development of more complex life.

Importance of Microvilli in Small Intestine

• Function: Increases surface area for absorption of nutrients (carbohydrates, lipids, proteins).

  • Aids in digestion and absorption processes.

Concept Maps

• A visual tool for organizing information and facilitating study.

  • Example: Linking cell types (e.g., prokaryotic vs. eukaryotic) and their unique features.